1. Related Art
Rapid Prototyping and Manufacturing (RP&M) is the name given to a field of technologies that can be used to form three-dimensional objects rapidly and automatically from three-dimensional computer data representing the objects. Rapid Prototyping and Manufacturing can be considered to include three classes of technologies: (1) stereolithography, (2) selective deposition modeling, and (3) laminated object manufacturing.
The stereolithography class of technologies creates three-dimensional objects by successively forming layers of a fluid-like medium adjacent to previously formed layers of medium and selectively solidifying these layers to form and adhere laminae (i.e. solidified layers). These laminae are solidified according to cross-sectional data representing successive slices of the three-dimensional object. Typically, adhesion between successive laminae occurs by chemical bond formation between the two laminae (e.g. inter-lamina cross-linking) during polymerization. In alternative embodiments, it is possible that adhesion could occur by application of a separate adhesive or by other mechanical bonding. In summary, adhesion may occur via an adhesive or cohesive phenomenon.
One specific stereolithography technology is known simply as stereolithography, and uses a liquid medium building material that is selectively solidified by exposing it to stimulation. The liquid medium is typically a photopolymerizable material (i.e. resin) and the stimulation is typically visible or ultraviolet electromagnetic radiation. The radiation is typically produced by a laser. Liquid-based stereolithography is disclosed in various patents, applications, and publications, of which a number are briefly described in the Related Patents, Applications and Publications section hereafter. Another stereolithography technology is known as selective laser sintering (SLS). Selective laser sintering is based on the selective solidification of layers of a powdered medium by exposing the layers to infrared electromagnetic radiation to sinter or fuse the particles. Selective laser sintering is described in U.S. Pat. No. 4,863,538 issued Sep. 5, 1989, to Deckard. A third technology is known as Three Dimensional Printing (3DP). Three-dimensional printing is based on the selective solidification of layers of a powdered medium which are solidified by the selective deposition of a binder thereon. Three-dimensional printing is described in U.S. Pat. No. 5,204,055 issued Apr. 20, 1993, to Sachs, et al.
The present invention is primarily directed to stereolithography using liquid-based building materials (i.e. medium). It is believed, however, that the techniques of the present invention may have application in the other stereolithography technologies for the purposes of enhancing thermal and/or vibrational stability.
Selective deposition modeling, SDM, involves the build-up of three-dimensional objects by selectively depositing solidifiable material on a lamina-by-lamina basis according to cross-sectional data representing slices of the three-dimensional object. One such technique is called fused deposition modeling, FDM, and involves the extrusion of streams of heated, flowable material which solidify as they are dispensed onto the previously formed laminae of the object. Fused deposition modeling is described in U.S. Pat. No. 5,121,329 issued Jun. 9, 1992, to Crump. Another technique is called Ballistic Particle Manufacturing, BPM, which uses a 5-axis, ink-jet dispenser to direct particles of a material onto previously solidified layers of the object. Ballistic particle manufacturing is described in PCT Publication Nos. WO 96/12607 published May 2, 1996, by Brown, et al.; WO 96/12608 published May 2, 1996, by Brown et al.; WO 96/12609 published May 2,1996, by Menhennett et al.; and WO 96/12610 published May 2, 1996, by Menhennett et al. A third technique called Multijet Modeling (MJM) involves the selective deposition of droplets of material from multiple ink jet orifices to speed the building process. Multijet modeling is described in PCT Publication Nos. WO 97/111835 published Apr. 3, 1997, by Earl et al.; and, WO 97/11837 published Apr. 3, 1997, by Leyden et al. (both assigned to 3D Systems, Inc., as is the instant application).
Though, as noted above, the techniques of the instant invention are directed primarily to liquid-based stereolithography object formation, it is believed that the techniques may have application in the selective deposition modeling technologies to enhance thermal and/or vibrational stability of the selective deposition modeling systems.
Laminated object manufacturing, LOM, techniques involve the formation of three-dimensional objects by the stacking, adhering, and selective cutting, in a selected order, of sheets of material, according to the cross-sectional data representing the three-dimensional object to be formed. Laminated object manufacturing is described in U.S. Pat. No. 4,752,352 issued Jun. 21, 1988, to Feygin; and U.S. Pat. No. 5,015,312 issued May 14, 1991, to Kinzie; and in PCT Publication WO 95/18009 published Jul. 6, 1995, by Morita et al.
It is believed that the techniques may have application in the laminated object manufacturing technologies to enhance thermal and/or vibrational stability of the laminated object manufacturing systems.
A need exists in the art for rapid prototyping systems with enhanced thermal and/or vibrational stability for the efficient production of accurate three-dimensional objects.
2. Other Related Patents, Applications and Publications
The patents, applications and publications mentioned above and hereafter are all incorporated by reference herein as if set forth in full. Table 1 provides a table of patents, applications and publications co-owned by the assignee of the instant application. A brief description of subject matter found in each patent, application and publication is included in the table to aid the reader in finding specific types of teachings. It is not intended that the incorporation of subject matter be limited to those topics specifically indicated, but instead the incorporation is to include all subject matter found in these publications, applications and patents. The teachings in these incorporated references can be combined with the teachings of the instant application in many ways. For example, the various apparatus configurations disclosed in these references may be used in conjunction with the novel features of the instant invention.
TABLE 1 Related Patents, Applications and Publications Patent/ Application/ Publication No. Inventor Subject U.S. Pat. No. 4,575,330 Hull Discloses fundamental elements of stereolithography. U.S. Pat. No. 4,999,143 Hull, et al. Discloses various removable support applicable to stereo- lithography. U.S. Pat. No. 5,058,988 Spence Discloses the application of beam profiling techniques useful in stereolithography for determin- ing cure depth, scanning velocity, etc. U.S. Pat. No. 5,059,021 Spence, Discloses the utilization et al. of drift correction techniques for eliminating errors in beam positioning resulting from instabilities in the beam scanning system. U.S. Pat. No. 5,076,974 Modrek, Discloses techniques for et al. post processing objects formed by stereolithography. In particular exposure techniques are described that complete the solidification of the building material. Other post processing steps are also disclosed such as steps of filing in or sanding off surface discontinues. U.S. Pat. No. 5,104,592 Hull Discloses various techniques for reducing distortion, and particularly curl type distortion, in objects being formed by stereo- lithography. U.S. Pat. No. 5,123,734 Spence, Discloses techniques for cali- et al. brating a scanning system. In particular, techniques for mapping from rotational mirror coordinates to planar target surface coor- dinates are disclosed. U.S. Pat. No. 5,133,987 Spence, Discloses the use of a et al. stationary mirror located on an optical path between the scanning mirrors and the target surface to fold the optical path in a stereolithography system. U.S. Pat. No. 5,174,931 Almquist, Discloses various doctor blade et al. configurations for use in forming layers of medium adjacent to previously solidified laminae. U.S. Pat. No. 5,182,056 Spence, Discloses the use of multiple et al. wavelengths in the exposure of a stereolithographic medium. U.S. Pat. No. 5,182,715 Vorgitch, Discloses various elements of a et al. large stereolithographic system. U.S. Pat. No. 5,184,307 Hull, et al. Discloses a program called Slice from application and various techniques for convert- No. 07/331,644 ing three-dimensional object data into data descriptive of cross-sect- ions. Disclosed techniques include line width compensation tech- niques (erosion routines), and object sizing techniques. The application giving rise to this patent included a number of appendices that provide further details regarding stereolithography methods and systems. U.S. Pat. No. 5,209,878 Smalley, Discloses various techniques for et al. reducing surface discontinuities between successive cross-sections resulting from a layer-by-layer building technique. Disclosed techniques include use of fill layers and meniscus smoothing. U.S. Pat. No. 5,234,636 Hull, et al. Discloses techniques for reducing surface discontinuities by coating a formed object with a material, heating the mat- erial to cause it to become flowable, and allowing surface tension to smooth the coating over the object surface. U.S. Pat. No. 5,238,639 Vinson, Discloses a technique for minimiz- et al. ing curl distortion by balancing upward curl to downward curl. U.S. Pat. No. 5,256,340 Allison, Discloses various build/exposure and et al. styles for forming objects including WO 95/29053 various techniques for reducing ob- ject distortion. Disclosed techniques include: (1) building hollow, partially hollow, and solid objects, (2) achieving more uniform cure depth, (3) exposing layers as a series of separated tiles or bullets, (4) using alternate sequencing exposure patterns from layer to layer, (5) using staggered or offset vectors from layer to layer, and (6) using one or more overlapping exposure patterns per layer. U.S. Pat. No. 5,321,622 Snead, Discloses a computer program et al. known as CSlice which is used to convert three-dimensional object data into cross-sectional data. Disclosed techniques include the use of various Boolean operations in stereolithography. U.S. Pat. No. 5,597,520 Smalley, Discloses various exposure and et al. techniques for enhancing object WO 95/29053 formation accuracy. Disclosed techniques address formation of high resolution objects from building materials that have a Minimum Solidification Depth greater than one layer thickness and/or a Minimum Recoating Depth greater than the desired object resolution. WO 97/11835 Thayer, Discloses build and support et al. styles for use in a Multi-Jet Modeling selective deposition modeling system. WO 97/11837 Earl, et al. Discloses data manipulation and system control techniques for use in a Multi-Jet Modeling selective deposition modeling system. U.S. Pat. No. 5,902,537 Almquist, Discloses various recoating et al. techniques for use in stereolitho- graphy, including 1) an ink jet dispensing device, 2) a fling recoater, 3) a vacuum applicator, 4) a stream recoater, 5) a counter rotating roller recoater, and 6) a technique for deriving sweep extents. U.S. Pat. No. 5,840,239 Partanen, Discloses the application of 5,840,239 et al. solid-state lasers to stereolithography. U.S. Pat. No. 6,001,257 Partanen, Discloses the use of a pulsed et al. radiation source for solidifying layers of building and in particular the ability to limit pulse firing locations to only selected target locations on a surface of the medium. U.S. Pat. No. 6,084,980 Nguyen, Discloses techniques for inter- et al. polating originally supplied cross- sectional data perspective of a three-dimensional object to pro- duce modified data descriptive of the three-dimensional object including data descriptive of intermediate regions between the originally supplied cross-sections of data. WO 98/51479 Manners, Discloses techniques for et al. identifying features of partially formed objects. Identifiable features include trapped volumes, effective trapped volumes, and solid features of a specified size. The identified regions can be used in automatically specifying recoat- ing parameters and or exposure parameters. U.S. Pat. No. 5,902,538 Kruger, Discloses simplifies techniques et al. for forming high resolution objects from materials posessing a mini- mum recoating depth (MRD) that is larger than a layer thickness resolution desired in forming objects. Building techniques include enhanced exposure and recoating techniques, with layers defined as primary or secondary. Recoating techniques are described which can be used when the thick- ness between consecutive layers is less than a leading edge bulge phenomenon. US 09/154,967 Nguyen, Discloses techniques for et al. stereolithographic recoating using a sweeping recoating device that pause and/or slows down over laminae that are being coated over. US 09/247,113 Chari, et Discloses improved stereolitho- al. graphic techniques for maintaining build chamber temperature at a desired level. The techniques include varying heat production based on ht e difference between a detected temperature and the desired temperature US 09/247,113 Everett, Discloses techniques forming et al. objects using varying production of prescribed stimulation (e.g. UV radiation). Production is reducing or eliminated during non-exposure periods (e.g. recoating, z-wait, and pre-dip delay). Production is set to a desired level based on the type of exposure that is desired.
The following two books are also incorporated by reference herein as if set forth in full: (1) Rapid Prototyping and Manufacturing: Fundamentals of Stereolithography, by Paul F. Jacobs; published by the Society of Manufacturing Engineers, Dearborn Mich.; 1992; and (2) Stereolithography and other RP&M Technologies: from Rapid Prototyping to Rapid Tooling; by Paul F. Jacobs; published by the Society of Manufacturing Engineers, Dearborn Mich.; 1996.